This invention relates to a magnetic disk device; and, more particularly, the invention relates to the structure of a magnetic head slider and to a magnetic disk in a contact recording magnetic disk device in which the magnetic head slider touches the magnetic disk.
To increase the recording density of a magnetic disk device, a narrowing of flying height, that is defined as the spacing between a magnetic head slider mounted with a magnetic head and a rotating magnetic disk, is important. A uniform flying height over the entire surface of the magnetic disk is also required. Further, any fluctuation of flying height due to environmental changes, especially a decrease of the flying height due to a drop in atmospheric pressure when operating at a high altitude, is required to be minimized. In proportion to a decrease in the flying height, the possibility of contact by the magnetic head slider with the magnetic disk increases; and, if the degree of contact is severe, the magnetic head slider crashes against the magnetic disk and there is a possibility of destroying the recorded data on the magnetic disk.
A technique for generally equalizing the flying height over the entire surface of the magnetic disk, for reducing a decrease of the flying height and for keeping a uniform flying height all over the magnetic disk when the disk is used at a high altitude, is disclosed by JP-A-2000-57724. This Japanese publication discloses a step air bearing sub-ambient pressure force magnetic head slider which generally equalizes the flying height over the entire surface of the magnetic disk and makes it possible to reduce a decrease of the flying height when the disk is used at a high altitude by the adequate combination of the rail surfaces with a step air bearing having a recess with a depth of sub-microns, the recess being deeper than that of the air bearing, for generating a sub-ambient pressure force.
One way to increase the recording density of a magnetic disk device, while maintaining a high reliability, is to devise measures for preventing contact between the magnetic head slider and the magnetic disk by narrowing and equalizing the flying height over the entire surface of the magnetic disk, by reducing fluctuation of the flying height caused by the variation of the manufacturing techniques of the magnetic head slider, by reducing fluctuation of the flying height during seek operations, and by reducing a decrease of flying height when the disk is used at a high altitude.
However, no matter what measures are taken to achieve the above-described effects, contact between the magnetic head slider and the magnetic disk is unavoidable with a narrow flying height of 15 nm or less, so that the vibration or the wear on the magnetic head slider are becoming a new problem.
Regarding the step air bearing sub-ambient pressure force magnetic head slider disclosed in JP-A-2000-57724, it is disclosed that the flying height is generally uniform, and that fluctuations in the flying height due to variation of the manufacturing tolerances, seek operations and use in a high altitude environment can be reduced. However, no consideration is given especially to the vibration of a magnetic head slider caused by contact with the magnetic disk, so that improvement on this point is needed.
The present invention relates to the above-described needs and intends to provide a magnetic disk device and a magnetic head slider that generally provide a uniform flying height over the entire surface of the magnetic disk, reduce fluctuations in the flying height due to variation of the manufacturing tolerances, during seek operations and use in a high altitude environment, and, in case of contact between the magnetic head slider and the magnetic disk, the magnetic head slider slides on the surface of the magnetic disk smoothly while maintaining a high reliability.
To solve above described problems, the present invention adopts the following technology.
A magnetic head slider comprising: on the air flow-out side, which is the closest to the magnetic disk in operation, a magnetic head mounting surface adjacent to while a magnetic head is mounted; a slider rail surface which is separated from said magnetic head mounting surface and forms a surface near to the air flow-in side, both side surfaces near the air flow-in edge having a depth of 10 nm to 50 nm from the magnetic head mounting surface; a slider step air bearing surface formed to surround said slider rail surface and having a depth of 50 nm to 200 nm from said slider rail surface; and a recess for generating a sub-ambient pressure force surrounding said slider step air bearing surface and having a depth of 400 nm to 1.3 xcexcm from said slider step air bearing surface.
A magnetic disk device is provided with the magnetic head slider mounted with a magnetic head and a magnetic disk that operates as a data recording medium, wherein the vicinity of said magnetic head of said magnetic head slider has the possibility of contacting said magnetic disk in operation, said magnetic head slider having a length of 1.25 mm or less, a width of 1 mm or less and a thickness of 0.3 mm or less, and the friction force exerted between said magnetic head slider and said magnetic disk is 10 mN or less.
A magnetic disk device is provided with a magnetic head slider having a magnetic head and a magnetic disk that operates as a data recording medium, wherein the vicinity of said magnetic head of said magnetic head slider has the possibility of contacting said magnetic disk in operation, the floating pitch angle of said magnetic head slider being 50 micro-radian or more, the mean surface roughness Ra of said magnetic disk being 2 nm or less and the peak count thereof being 700/400 xcexcm2 or more.